[PATCH v5] objcopy: add option to specify custom prefix for symbol of binary input
Alon Bar-Lev
alon.barlev@gmail.com
Mon Oct 27 13:53:48 GMT 2025
When using --input-target=binary, objcopy currently derives symbol names
from a mangled version of the input file name. This approach can lead to
unpredictable results, as the generated symbols depend on the file path and
working directory.
This patch introduces a new option:
--binary-symbol-prefix <prefix> Use <prefix> as the base symbol name for
the input file (default: derived from
file name)
It allows specifying an explicit symbol prefix, while preserving the existing
behavior as a fallback.
Signed-off-by: Alon Bar-Lev <alon.barlev@gmail.com>
---
bfd/bfd-in2.h | 15 +++++++++
bfd/bfd.c | 15 +++++++++
bfd/binary.c | 18 +++++++---
binutils/doc/binutils.texi | 15 +++++++++
binutils/objcopy.c | 24 +++++++++----
binutils/testsuite/binutils-all/objcopy.exp | 37 +++++++++++++++++++++
6 files changed, 114 insertions(+), 10 deletions(-)
diff --git a/bfd/bfd-in2.h b/bfd/bfd-in2.h
index 5e7c6ddf1ee..7ceecda1d8c 100644
--- a/bfd/bfd-in2.h
+++ b/bfd/bfd-in2.h
@@ -1949,6 +1949,9 @@ struct bfd
/* The filename the application opened the BFD with. */
const char *filename;
+ /* The symbol name for the file or NULL. */
+ const char *binary_symbol_prefix;
+
/* A pointer to the target jump table. */
const struct bfd_target *xvec;
@@ -2293,6 +2296,18 @@ bfd_get_filename (const bfd *abfd)
return abfd->filename;
}
+static inline const char *
+bfd_get_binary_symbol_prefix (const bfd *abfd)
+{
+ return abfd->binary_symbol_prefix;
+}
+
+static inline void
+bfd_set_binary_symbol_prefix (bfd *abfd, const char * const val)
+{
+ abfd->binary_symbol_prefix = val;
+}
+
static inline bool
bfd_get_cacheable (const bfd *abfd)
{
diff --git a/bfd/bfd.c b/bfd/bfd.c
index 858ab5ce017..417a4225be2 100644
--- a/bfd/bfd.c
+++ b/bfd/bfd.c
@@ -105,6 +105,9 @@ CODE_FRAGMENT
. {* The filename the application opened the BFD with. *}
. const char *filename;
.
+. {* The symbol name for the file or NULL. *}
+. const char *binary_symbol_prefix;
+.
. {* A pointer to the target jump table. *}
. const struct bfd_target *xvec;
.
@@ -452,6 +455,18 @@ EXTERNAL
. return abfd->filename;
.}
.
+.static inline const char *
+.bfd_get_binary_symbol_prefix (const bfd *abfd)
+.{
+. return abfd->binary_symbol_prefix;
+.}
+.
+.static inline void
+.bfd_set_binary_symbol_prefix (bfd *abfd, const char * const val)
+.{
+. abfd->binary_symbol_prefix = val;
+.}
+.
.static inline bool
.bfd_get_cacheable (const bfd *abfd)
.{
diff --git a/bfd/binary.c b/bfd/binary.c
index 7fe47b590de..7d5ac46ed7e 100644
--- a/bfd/binary.c
+++ b/bfd/binary.c
@@ -122,18 +122,28 @@ static char *
mangle_name (bfd *abfd, char *suffix)
{
bfd_size_type size;
+ const char *prefix;
+ const char *prefix_amend = "";
char *buf;
char *p;
- size = (strlen (bfd_get_filename (abfd))
- + strlen (suffix)
- + sizeof "_binary__");
+ prefix = bfd_get_binary_symbol_prefix (abfd);
+ if (prefix == NULL)
+ {
+ prefix = "_binary_";
+ prefix_amend = bfd_get_filename (abfd);
+ }
+
+ size = strlen (prefix)
+ + strlen (prefix_amend)
+ + strlen (suffix)
+ + 2;
buf = (char *) bfd_alloc (abfd, size);
if (buf == NULL)
return "";
- sprintf (buf, "_binary_%s_%s", bfd_get_filename (abfd), suffix);
+ sprintf (buf, "%s%s_%s", prefix, prefix_amend, suffix);
/* Change any non-alphanumeric characters to underscores. */
for (p = buf; *p; p++)
diff --git a/binutils/doc/binutils.texi b/binutils/doc/binutils.texi
index 89425b8a15b..c0a09a373f9 100644
--- a/binutils/doc/binutils.texi
+++ b/binutils/doc/binutils.texi
@@ -1315,6 +1315,7 @@ objcopy [@option{-F} @var{bfdname}|@option{--target=}@var{bfdname}]
[@option{--keep-global-symbols=}@var{filename}]
[@option{--localize-symbols=}@var{filename}]
[@option{--weaken-symbols=}@var{filename}]
+ [@option{--binary-symbol-prefix}@var{string}]
[@option{--add-symbol} @var{name}=[@var{section}:]@var{value}[,@var{flags}]]
[@option{--alt-machine-code=}@var{index}]
[@option{--prefix-symbols=}@var{string}]
@@ -1554,6 +1555,20 @@ given more than once. Note - unique symbols are not converted.
@itemx --weaken-symbol=@var{symbolname}
Make symbol @var{symbolname} weak. This option may be given more than once.
+@item --binary-symbol-prefix=@var{string}
+When used with @option{--input-target=binary}, sets @var{string} as the
+base name for the symbols generated for the input file. These symbols are:
+
+@example
+@var{string}_start
+@var{string}_end
+@var{string}_size
+@end example
+
+By default, the binary input handler derives the prefix symbol name from a
+mangled version of the input file name and _binary prefix. This option
+allows specifying it explicitly.
+
@item --globalize-symbol=@var{symbolname}
Give symbol @var{symbolname} global scoping so that it is visible
outside of the file in which it is defined. This option may be given
diff --git a/binutils/objcopy.c b/binutils/objcopy.c
index 9373b75d6ed..6613af01bab 100644
--- a/binutils/objcopy.c
+++ b/binutils/objcopy.c
@@ -334,6 +334,7 @@ enum command_line_switch
OPTION_HEAP,
OPTION_IMAGE_BASE,
OPTION_IMPURE,
+ OPTION_INPUT_SYMBOL,
OPTION_INTERLEAVE_WIDTH,
OPTION_KEEPGLOBAL_SYMBOLS,
OPTION_KEEP_FILE_SYMBOLS,
@@ -465,6 +466,7 @@ static struct option copy_options[] =
{"info", no_argument, 0, OPTION_FORMATS_INFO},
{"input-format", required_argument, 0, 'I'}, /* Obsolete */
{"input-target", required_argument, 0, 'I'},
+ {"binary-symbol-prefix", required_argument, 0, OPTION_INPUT_SYMBOL},
{"interleave", optional_argument, 0, 'i'},
{"interleave-width", required_argument, 0, OPTION_INTERLEAVE_WIDTH},
{"keep-file-symbols", no_argument, 0, OPTION_KEEP_FILE_SYMBOLS},
@@ -678,6 +680,9 @@ copy_usage (FILE *stream, int exit_status)
--globalize-symbols <file> --globalize-symbol for all in <file>\n\
--keep-global-symbols <file> -G for all symbols listed in <file>\n\
--weaken-symbols <file> -W for all symbols listed in <file>\n\
+ --binary-symbol-prefix <prefix>\n\
+ Use <prefix> as the base symbol name for the input file\n\
+ (default: derived from file name)\n\
--add-symbol <name>=[<section>:]<value>[,<flags>] Add a symbol\n\
--alt-machine-code <index> Use the target's <index>'th alternative machine\n\
--writable-text Mark the output text as writable\n\
@@ -3858,9 +3863,10 @@ copy_archive (bfd *ibfd, bfd *obfd, const char *output_target,
/* The top-level control. */
static void
-copy_file (const char *input_filename, const char *output_filename, int ofd,
- struct stat *in_stat, const char *input_target,
- const char *output_target, const bfd_arch_info_type *input_arch)
+copy_file (const char *input_filename, const char *binary_symbol_prefix,
+ const char *output_filename, int ofd, struct stat *in_stat,
+ const char *input_target, const char *output_target,
+ const bfd_arch_info_type *input_arch)
{
bfd *ibfd;
char **obj_matching;
@@ -3891,6 +3897,7 @@ copy_file (const char *input_filename, const char *output_filename, int ofd,
status = 1;
return;
}
+ bfd_set_binary_symbol_prefix(ibfd, binary_symbol_prefix);
switch (do_debug_sections)
{
@@ -5093,7 +5100,7 @@ strip_main (int argc, char *argv[])
}
status = 0;
- copy_file (argv[i], tmpname, tmpfd, &statbuf, input_target,
+ copy_file (argv[i], NULL, tmpname, tmpfd, &statbuf, input_target,
output_target, NULL);
if (status == 0)
{
@@ -5341,6 +5348,7 @@ static int
copy_main (int argc, char *argv[])
{
char *input_filename = NULL;
+ char *binary_symbol_prefix = NULL;
char *output_filename = NULL;
char *tmpname;
char *input_target = NULL;
@@ -5395,6 +5403,10 @@ copy_main (int argc, char *argv[])
input_target = optarg;
break;
+ case OPTION_INPUT_SYMBOL:
+ binary_symbol_prefix = optarg;
+ break;
+
case 'O':
case 'd': /* "destination" - 'O' is preferred */
output_target = optarg;
@@ -6197,8 +6209,8 @@ copy_main (int argc, char *argv[])
input_filename, strerror (errno));
}
- copy_file (input_filename, tmpname, tmpfd, &statbuf, input_target,
- output_target, input_arch);
+ copy_file (input_filename, binary_symbol_prefix, tmpname, tmpfd, &statbuf,
+ input_target, output_target, input_arch);
if (status == 0)
{
const char *oname = output_filename ? output_filename : input_filename;
diff --git a/binutils/testsuite/binutils-all/objcopy.exp b/binutils/testsuite/binutils-all/objcopy.exp
index b11b17e012c..fc589b84e1e 100644
--- a/binutils/testsuite/binutils-all/objcopy.exp
+++ b/binutils/testsuite/binutils-all/objcopy.exp
@@ -1602,3 +1602,40 @@ proc objcopy_tek2bin {} {
}
objcopy_tek2bin
+
+# Test input symbol
+
+proc input_symbol {name file args symbol} {
+ global OBJCOPY
+ global NM
+ global NMFLAGS
+
+ set test "input symbol ($name)"
+
+ # detect a valid target, take the first supported
+ set target [lindex [split [binutils_run $OBJCOPY "--info"] \n] 1]
+
+ set out tmpdir/input_symbol.o
+ set got [binutils_run $OBJCOPY "-I binary -O $target $args $file $out"]
+
+ set expected [list "${symbol}_end" "${symbol}_size" "${symbol}_start"]
+
+ set exec_output [binutils_run $NM "-a $NMFLAGS $out"]
+ set exec_output [prune_warnings $exec_output]
+ set actual {}
+ while {[regexp {^[0-9a-fA-F]+?[ ]+[TtDdA] ([0-9a-zA-Z_]+)[\r\n]+(.*)$} ${exec_output} all s rest]} {
+ set actual [concat $actual $s]
+ set exec_output $rest
+ }
+
+ if {[lsort $expected] ne [lsort $actual]} {
+ send_log "expected: $expected, actual: $actual\n"
+ fail $test
+ return
+ }
+
+ pass $test
+}
+
+input_symbol implicit $srcdir/$subdir/version.s "" _binary_[regsub -all {[^0-9a-zA-Z]} $srcdir/$subdir/version.s _]
+input_symbol explicit $srcdir/$subdir/version.s "--binary-symbol-prefix symbol1" symbol1
--
2.43.0
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